/* * helper functions for SG DMA video4linux capture buffers * * The functions expect the hardware being able to scatter gather * (i.e. the buffers are not linear in physical memory, but fragmented * into PAGE_SIZE chunks). They also assume the driver does not need * to touch the video data. * * (c) 2007 Mauro Carvalho Chehab, * * Highly based on video-buf written originally by: * (c) 2001,02 Gerd Knorr * (c) 2006 Mauro Carvalho Chehab, * (c) 2006 Ted Walther and John Sokol * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 */ #ifndef _VIDEOBUF_DMA_SG_H #define _VIDEOBUF_DMA_SG_H #include /* --------------------------------------------------------------------- */ /* * A small set of helper functions to manage buffers (both userland * and kernel) for DMA. * * videobuf_dma_init_*() * creates a buffer. The userland version takes a userspace * pointer + length. The kernel version just wants the size and * does memory allocation too using vmalloc_32(). * * videobuf_dma_*() * see Documentation/DMA-API-HOWTO.txt, these functions to * basically the same. The map function does also build a * scatterlist for the buffer (and unmap frees it ...) * * videobuf_dma_free() * no comment ... * */ struct videobuf_dmabuf { u32 magic; /* for userland buffer */ int offset; size_t size; struct page **pages; /* for kernel buffers */ void *vaddr; struct page **vaddr_pages; dma_addr_t *dma_addr; struct device *dev; /* for overlay buffers (pci-pci dma) */ dma_addr_t bus_addr; /* common */ struct scatterlist *sglist; int sglen; int nr_pages; int direction; }; struct videobuf_dma_sg_memory { u32 magic; /* for mmap'ed buffers */ struct videobuf_dmabuf dma; }; /* * Scatter-gather DMA buffer API. * * These functions provide a simple way to create a page list and a * scatter-gather list from a kernel, userspace of physical address and map the * memory for DMA operation. * * Despite the name, this is totally unrelated to videobuf, except that * videobuf-dma-sg uses the same API internally. */ int videobuf_dma_free(struct videobuf_dmabuf *dma); int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma); struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf); void *videobuf_sg_alloc(size_t size); void videobuf_queue_sg_init(struct videobuf_queue *q, const struct videobuf_queue_ops *ops, struct device *dev, spinlock_t *irqlock, enum v4l2_buf_type type, enum v4l2_field field, unsigned int msize, void *priv, struct mutex *ext_lock); #endif /* _VIDEOBUF_DMA_SG_H */ v>

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